/*   
 * Copyright 2010 Rob Schoening
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *    http://www.apache.org/licenses/LICENSE-2.0
 *    
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.beaconframework.util.expression;

import java.util.Map;

import org.springframework.expression.Expression;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;

public class SpringExpressionEngineFactory extends ExpressionEngineFactory {

    public class SpringExpressionEngine implements ExpressionEngine {
        @Override
        public Object evaluate(String expressionString, Map<String, Object> vars) {
            Expression expression = new SpelExpressionParser()
                    .parseExpression(expressionString);

            StandardEvaluationContext ctx = new StandardEvaluationContext();
            ctx.setVariables(vars);
            ctx.setRootObject(vars.get("root"));

            return expression.getValue(ctx);
        }
    }

    @Override
    public ExpressionEngine getExpressionEngine() {
        return new SpringExpressionEngine();
    }
}
